1. Field of the Invention
The present invention relates to devices for performing percutaneous surgeries and, more specifically, to surgical cannulae.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Traditional minimally-invasive arthroscopic surgeries are performed using a cannula device to penetrate small incisions in the patient's skin and outer tissue, creating a port through which surgical tools may be passed to allow access to the underlying structure of interest. For example, in shoulder arthroscopy, the procedure is performed through “portals” in the patient's skin. These portals are formed from small incisions, generally about ½ of an inch to an inch long in the skin, and are located over particular areas of the joint that the surgeon will need to operate upon. Cannulas are then inserted into the portals so that instruments can easily be placed in the shoulder joint. Shoulder arthroscopy itself involves inserting a specially designed video camera with a very bright fiber optic light source into the shoulder joint so that the important parts of the joint can be seen. Instruments that have been specially designed to remove inflamed tissue, attach sutures to bone, and repair tears and damaged tendons are then used to operate inside the shoulder.
The area between the skin tissue and shoulder joint is quite small. Consequently, it is necessary to “inflate” the area by pumping saline fluids into the joint under pressure. This pressure pushes the tissue outward from the joint and allows greater room for manipulation of the arthroscopic camera and other surgical tools. However, the actual working angle of the tools is ultimately determined by the length and inner diameter of the cannula. Heavy patients or patients with large amounts of skin and other tissue covering the joint require a longer cannula to penetrate the tissue sufficiently for the procedure. This increased cannula length decreases the working angle of the tools at the joint, limiting the ability of the surgeon to perform the procedure. Although this angle may be increased by increasing the inner diameter of the cannula, there are realistic limits on the useable diameter. For example, the diameter can only be increased by a small amount or else it would effectively eliminate any benefit of conducting the arthroscopic procedure as the portal size could become the equivalent of a large incision as performed in traditional surgery.
What is needed is a cannula device that is capable of compressing the tissue through which it penetrates, and that is relatively simple to insert and remove so as to minimize tissue damage to the patient.